Pocket-size folding device with integrated electrodes for recording, processing and transmission with three ECG leads is a hand held ECG device with integrated electrodes used to measure, process and transmit three ECG leads to the remote diagnostic center. When in closed position and not in use the device is more compact and robust so it can be carried in a pocket or a pouch while electrodes are protected from getting dirty or damaged When opening it into a measuring position it becomes ergonomic. It is well adapted to the shape of a user's chest which ensures stable and reliable contact between chest electrodes (4-6) and chest surface. Finger electrodes (7,8) are designed for a contact with left hand and right hand thumbs as well as supporting the device and ensuring sufficient pressure to the chest without intense use of user's arms. The device is compact, it doesn't use cables or levers which makes it very easy to use.